The inaccuracy of total uterine volume measurements: sources of error and a proposed solution

Inaccuracies in total intrauterine volumes calculated using the prolate ellipse equation have been reported. No previous study has examined all the sources of error. In this study, a comprehensive approach was undertaken. Measurements were obtained from scans of the pregnant uterus in the prone position using an automated water-path scanner (Octoson) and in the supine position using standard static B-mode scanners. Several conclusions could be drawn: 1) From the Octoson prone scans, uterine volumes obtained using the prolate ellipse formula were markedly different from the true uterine volumes obtained by the summation of stepped areas. This showed that the prolate ellipse formula was inaccurate. 2) From the static supine scans, many observer inconsistencies were found in uterine volumes obtained from the prolate ellipse formula. This made the prolate ellipse formula unreliable. 3) Previously published graphs calculated from the prolate ellipse equation, comparing fetal age with total intrauterine volume, were found to vary accuracy, presumably as a result of 1 and 2. A more accurate approach is proposed. Using the outer uterine wall as the boundary, the stepped area-to-volume values of transverse scans taken at 3-cm intervals were found to closely approximate true volumes, with an average error of only 3.5 per cent. Since these measurements encompass the intrauterine contents and the myometrium, it is suggested that the term "total uterine volume" be used instead of "total intrauterine volume."     

The Kimray-Greenfield filter: evaluation by duplex real-time/pulsed Doppler ultrasound

The Kimray-Greenfield filter is a wire cage which is inserted into the inferior vena cava (IVC) to prevent thrombi originating in pelvic and leg veins from embolizing to the lungs. Duplex real-time/pulsed Doppler ultrasound was used to evaluate placement and function in 38 patients (46 examinations). Real-time examination successfully identified the IVC and filter in 89% of cases. Pulsed Doppler studies demonstrated flow above and below the filter in 76%, accurately predicting normal flow in most cases. In 4 patients, Doppler scans revealed little or no flow distal to the filter; contrast cavograms confirmed obstruction secondary to thrombosis. This appears to be an accurate, noninvasive method of assessing postoperative reliability of the Kimray-Greenfield filter.     

Ultrasound mammography for male breast enlargement.

Fourteen men referred for ultrasound evaluation of breast enlargement had ultrasound mammography using water path techniques. Gynecomastia, both the localized type and the diffuse type, could be differentiated from the normal soft tissues of the chest wall on the B-scans. Among nine cases of men who underwent excision, there were six cases of gynecomastia, two lipomas, and one biopsy revealed normal subcutaneous tissue. The ultrasound B-scan images are correlated with the histologic findings in these nine cases. Ultrasound mammography using water path techniques is a useful imaging examination for male breast enlargement.     

Outpatient therapy of intra-abdominal abscesses following early discharge from the hospital

Although percutaneous aspiration and drainage of abdominal abscesses will frequently avert an open surgical procedure, patients remain hospitalized during drainage. The authors treated 9 patients for abscesses using percutaneous drainage catheters and sent them home with the catheter in place. All had an uneventful recovery. An average of $12,050 was saved in each case. The authors suggest that outpatient drainage of abdominal abscesses is significantly less expensive than inpatient treatment, yet does not jeopardize patient care.     

In vivo acoustic attenuation in liver: correlations with blood tests and histology

Results of in vivo attenuation measurements in the liver have been obtained in 26 normal controls and in 51 patients with chronic diffuse liver disease. A modified real-time sector scanner was used for narrow-band amplitude attenuation examination. In the control group (people without apparent liver disease), a statistically significant correlation was found between acoustic attenuation in liver and two blood tests reflecting liver function: serum albumin (n = 24, r = 0.67, p = 0.002) and prothrombin time (n = 23, r = 0.63, p = 0.019). There was a statistically significant positive correlation between attenuation and fat for all biopsied patients (n = 51, r = 0.32, p = 0.023) and for patients with minimal fibrosis (n = 25, r = 0.45, p = 0.027). Although no correlation with fibrosis was found for all patients, in the group of patients with minimal fat there was a correlation with portal fibrosis (n = 33, r = 0.37, p = 0.035). This double blind prospective study shows that in the liver: (1) attenuation estimates appear correlated with clinical parameters (blood tests) in normal volunteers, and (2) large changes in fat affect narrow-band acoustic attenuation estimates to a greater degree than severe portal fibrosis in patients with chronic diffuse liver disease. Further research is needed before these estimates can become a clinical tool.